Hydrosilylation is a reaction in which silicon-bonded hydrogen adds across an aliphatically unsaturated carbon-carbon bond under catalysis by a hydrosilylation catalyst such as chloroplatinic acid, platinum-alkenylsiloxane complexes, and platinum-olefin complexes.
Carbon-silicon bonds can be easily generated by this reaction, and as a consequence, it has found use in reactions for the synthesis of a variety of organosilanes, silicon-containing organic compounds, and organopolysiloxanes. It is also employed as a crosslinking reaction for curable organopolysiloxane compositions.
However, as shown in Japanese Patent Publication Kokoku Number Sho 58-17226 (17,226/1983)U.S. Pat. No. 4,248,751; Japanese Patent Application Laid Open Kokai/Unexamined Numbers Sho 62-257939 (257,939/1987)/U.S. Pat. No. 4,761,454; and Sho 63-6053 (6,053/1988)/U.S. Pat. No. 4,791,029; execution of hydrosilylation reactions in water has been associated with an inhibition of activity of the hydrosilylation catalyst by water, and hence a failure of hydrosilylation to proceed rapidly and the necessity for long periods of time for the reaction to reach completion.
Addition of large amounts of hydrosilylation catalyst to accelerate the reaction under these conditions leads to problems such as only a localized development of hydrosilylation, and discoloration due to the large amounts of catalyst employed.